If your vehicle is showing valve stem is cracked, leaking, or missing its cap, here are the most likely causes and the parts you'll need to fix each one.
Over time, rubber valve stems dry out from UV exposure and weather, becoming brittle and cracking at the base, which leads to slow air leaks.
Without a dust cap, dirt, water, and road grime can enter the valve core. This causes the internal spring mechanism to stick or corrode, resulting in a leak.
Metal TPMS valve stems are highly susceptible to corrosion, especially in areas that use road salt. The metal weakens and cracks, or the retaining nut seizes and breaks the stem.
If a technician over-tightens the retaining nut on a metal stem, or uses excessive force pulling a rubber stem through the wheel hole, it can tear or stress-fracture the stem.
Scraping against a curb, hitting a deep pothole, or catching road debris can physically snap or bend the valve stem, causing an immediate and rapid loss of air.